At night if over 60f or so outside oscillating fan is on.
We would call this phenomenon "winter". Or, at least, November.

My chickens would be digging their sweaters out of storage.
I dunno, I've pulled some pretty damp birds out of boxes for fair check in. To be fair those birds almost always had issues other than being damp thpugh, and I can promise they weren't damp from just having been washed.
Sounds like a ventilation problem. Or roof leaks. Top-hinged nest boxes are notorious for leaking at the hinge.